Double-depth drop-shelf dispensing mechanism



pe having side provided with shelf e, including a comwhich permits ae-by-side pairs of permit the use of a 2/1952 Coffing............ 5/1959Gabrielsen 'FOREIGN PATENTS ,966 /1896 Great Britain................8/1956 GreatBritain...............

Coleman Schmidt, Johnson, l-iovey, Williams & Chase g machine of the tydrop-shelf di ensing assemblies is nd control structur y reciprocableactuating bar,

gement ofa number of sid releasing mechanisms single bar between the frpair and operable such the mechanisms is in th Primary Examiner-SamuelF. Attorney- ABSTRACT: A vendin hinged releasing mechanisms a mom,vertical] double-depth arran shelf columns. The

Elmer Bradley Oiiutt Independence, Missouri 698,208 Jan. 16,1968

[] Patented Nov.17, 1970 [73] Assignee The Vendo Com Kansas City,

MECHANISM 17 Claims, 17 Drawing Figs. [52] United States Patent [72]inventor [2i] AppLNo.

[22] Filed [54] DOUBLE-DEPTH DROP-SIlEL [51] Int.

out and rear stack of shelves of each 8919031 81 that the force whicheffects release of e same direction as gravity. The shelves are releasedconsecutively from the bottom to the top of one stack and thence fromthe bottom to the top of the other stack. Switching apparatus permitsinitial setting for vending to commence either at the bottom of thefront stack or the Field [56] References Cited UNITED STATES PATENTS3,043,475 7/1962 Childers et al..... 3,167,215 1/1965 Holstein et a1...2,203,847

bottom of the rear stack.

6/1940 Steiner......................::.

' Patented Nov. 17, 1970 v 3,540,620

INVENTOR Elmer Bradley Offuff BY J I R EYS.

Patented Nov. 17, 1970 Sheet Qw v 4 M a .W 6 mm m u W 6 m0 m HM H I I Mm V, In. [IV m 4 I W l B I w s 4 m i 0 9 9 W 6 a w. "a m l M m I; 7 m a-;m\ M IH+I H\\ l l B I 9 W ,wfiv M5 w w 4 H I ll iii Patented Nov. 17,1970 3,540,620

Sheet 3 of 4 50 5 I08 110 52 50 INVENTOR [Ir/76f Bradley Offuff wb'wwqw?ATT EYS.

DOUBLE-DEPTH DROP-SHELF DISPENSING MECHANISM It is an important objectof the present invention to provide a vending machine having maximumspace conserving characteristics, by doubling the number of shelveswithout increasing the width of the front of the machine, through use offront and rear drop shelf columns, together with novel shelf releasingmechanisms permitting use of a common actuating bar that requires verylittle space and utilizes force of gravity in its operation, I

Another very important object of the instant invention is to provide avending machine of the aforementioned character which permits, each timethe machine is serviced, setting of the cycle of operation by theservice man in a manner to cause initial vending of old merchandise, sothat, for the most part, the fresh new products replenished by theserviceman are the last to be vended.

Other features of my present invention include novel shelf releasingmechanisms and control structure making the above objects possible, allto be made clear as the following specification progresses, referencebeing had to the accompanying drawings, wherein:

FIG. 1 is a side elevational view of one unit having a pair ofdouble-depth dropshelf dispensing mechanisms for vending machines madepursuant to my present invention;

FIG. 2 is a top plan view ofthe unit of FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken on line 3-3 of FIG. 1;

FIG. 4 is a view similar to FIG. 3 except for different positions of thereleasable mechanism of the upper shelf of the front stack and theholding means for the releasable mechanism of the lower shelf of therear stack;

FIG. 5 is a cross-sectional view taken on line 5-5 of FIG. 3;

FIG. 6 is a cross-sectional view taken on line 6-6 of FIG. 5;

FIG. 7 is a fragmentary top plan view showing a portion of the supportfor the unit of FIG. 1 and associated sold-out arrangement;

FIG. 8 is across-sectional view taken on line 8-8 of FIG. 7;

FIG. 9 is 'an enlarged, fragmentary, elevational view of a portion ofthe unit showing that side thereof opposite to FIG. 1 with parts brokenaway and in section for clearness;

FIG. 10 is a fragmentary front elevational view of the unit shown inFIG. 1;

FIGS. 11 and 12 are cross-sectional views taken on lines 11-11 and'12-12 respectively-of FIG. 9 but rotated l 80;

FIG. 13 is a detailed view similar to FIG. 1 showing a differentposition of one of the releasable mechanisms; and

FIGS. 14- 17 are schematic views showing various positions of thereleasable mechanisms.

Unit 20 includes a front and a rear U-shaped support 22 and 24respectively having their bights 26, 28 joined by upper track 30 andlower track 32. Flanges 34 and 36 of support 22 receive hinge pins 38for a stack of vertically spaced, front, ar-

ticle-retainin g shelves 40, and flanges 42 and 44 of support 24 receivehinge pins 46 for a stack of vertically spaced, rear, article-retainingshelves 48. When the shelves are horizontal (FIG. 10) they are in theirarticle-holding condition; when vertical (FIG. 10) they are in theirarticle discharge condition. Opposed extensions 50 from flanges 36 and44 are joined by crossbars 52.

Since the releasable mechanisms between flanges 36 and 44 for each ofthe shelves 40 and 48 respectively are identical, one only, inconnection with one of the front shelves 40, will be described. Itincludes a part or element 54 rigidly secured Wire latch 56 hasaV-shaped portion 66, the apex of which is retainedinslot 68 at thecorner between flange 36 and extension 50. The free end of portion 66 ishooked into a projection 70 struck from flange 36. The upper leg ofportion 66 is shiftable in a slot (FIGS. 11 and 12) formed in aprojection 72 struck from flange 36, such upper leg terminating in an L-shaped portion 74 that is offset from flange 36 and normally engages ear64 therebeneath. Thus, an upwardly inclined force on portion 66 withrespect to projection 72, releases ear 64 for gravitational movement ofshelf 40 to its vertical position.

Each element 54 has a pivot pin 76 rigid thereto and parallel with pin38 which carries plate 78 of a swingable latch release arm or triggermeans 80, plate 78 having a trip-engaging tab 82 and a lock-engagingtang 84, the latter of which is provided with a tongue 86 and alatch-engaging finger 88.

In addition to the ear 64, each element 54 has lock means in the natureof a normally upstanding leg 90 provided with an uppermost edge 92 and aprong 94. Except for the uppermost and the lowermost lock means, eachedge 92 normally has the tang 84 next above in engagement therewith. Theupper ends of prongs 94 of the two uppermost lock means normally supportother components, as hereinafter explained.

During'shelf resetting the prong 94 maintains engagement with the tang84 of the latch release arm or trigger 80 thereabove to prevent the leg90 of the element 54 from getting on the wrong side of the trigger 80.When a trigger 80 is driven, by means to be described, to effect releaseof the corresponding shelf, the edge 92 of the element 54 of that shelfdrops away from normal supporting relation to the trigger 80 of theshelf thereabove' causing that trigger to swing downwardly until the endof finger 88 engages the latch 56 of the latter shelf. 7

Control structure for the mechanisms above described. includes avertically reciprocable bar 96 between the flanges36 and 44 normallyresting on a stop 98 and held to a rectilinear path of travel by slottedguide 100 adjacent stop 98 as well as by slotted guides 102 and 104 ontrack 30 and uppermost crossbar 52-respectively. Bar 96, common to themechanisms of the two stacks of shelves 40 and 48, has trip means forthe triggers 80 inthe nature of opposed pairs of laterally extendtoshelf 40 for swinging movement therewith and a part 56, 7

ing lugs 106 adapted to engage the tabs 82.

The control structure includes also a novel switching ap paratus havinga pair of shiftable lever devices 108 and 110 swingable about ahorizontal shaft 112 carried by the exten- I sions 50, 50 and extendinginto overlying relationship to the two uppermost prongs 94.Additionally, there is provided a pair of releasable lever members 114and 116, carried by the lowermost crossbar 52 by hooks 117 for up anddown swinging movement, into and out of engagement with the lowermotangs 84.

Device 108 and member 114 correspond to shelves 40; device 110 andmember 116 correspond to shelves 48. Device 108 is coupled'with member116 by a pull rod 118 through coil spring 120 on rod 118 below member116. A pull rod 122, crossing rod 118, couples device 110 with member114 through a coil spring 124 on rod 122 below member 114.

An L-shaped projection 126 on the lowermost crossbar 52 holds bar 96 inthe guide 100 and supports a switching plate 128 for swinging movementabout upright pintle 129. -Upstanding handles 130 and 132, which may bemarked front and rear" respectively, are integral with plate 128. Whenhandle 130 is turned out, as shown in FIGS. 1 and 3-6, it slides plate128 beneath a strip 134 on the lowermost crossbar 52 and cams the member114 downwardly, out of engagement with the tang 84 thereabove,compressing spring 124, by engagement with inclined edge 136 of anupturned piece 138 integral with member 114. Conversely, when handle 132is turned out (not shown) it slides plate 128 beneath a strip 140 on thelowermost crossbar 52 and cams the member 116 downwardly, out ofengagement with the tang 84 thereabove, compressing spring 120, byengagement with inclined edge 142 of an .upturned piece 144 integralwith the member 116.

Compression of springs 120 and 124, as aforesaid, is caused by the factthat the devices 108 and 110 are being held upwardly, preventingdownward movement of rods 118 and 122, by the corresponding uppermostprongs 94 upon which devices 108 and 110 rest when the two uppermostshelves 40 and 48 are horizontal. FIG. 8 shows device 110 held up by theproximal prong 94, and illustrates device 108 lowered.

A leaf spring 146, held rigid on projection 126, has opposed, upturnedends 148 that are received alternately by hole 150 of plate 128 toyieldably maintain plate 128 in either of its two operating positions. 7

When all of the shelves 40 and 48 have been released, both of thedevices 108 and 110 will have dropped, thereby lowering an actuator 152for a sold-out switch 154 (FIG. 7); upstanding triangles 156 on thedevices 108 and 110 normally hold actuator 152 elevated as shown in FIG.8. Actuator 152 and switch 154 are mounted on a cabinet frame member 158along which track 30 slides when the unit 20 is pulled out for servicingthe shelves 40 and 48, track 32 also having a similar guide (not shown)in the cabinet. Manifestly, a front door of the vending machine cabinetis opened to render all of the side-by-side units accessible.

At the commencement of such servicing, the serviceman must first flipall of the empty shelves to their horizontal position where they areautomatically caught by the latches 56, i.e., the ears 64 deflect theportions '74 and slip into place thereabove. This is accomplished byrunning his fingers along the ends of shelves 40 and 48 remote fromflanges 36 and 44 and progressively raising the shelves from bottom totop.

The lowermost shelves 40 and 48, however, of each unit 20 must be raisedbefore the same can be pulled out for resetting the shelves as abovedescribed, since associated structure (not shown) would interfere withthe movement of the shelves while in the vertical position thereof. Thelowermost shelf 48 may be difficult to reach for such purpose;therefore, a handle 160 at the front of unit 20 below shelves 40 may beturned to rotate rod 162 and move a deflector 164 against the lowermostshelf 48 to raise the latter from its vertical position until it becomeslatched in place.

OPERATION With reference to but one of the units 20 of the machine, andassuming that all of the shelves 40 and 48 are horizontal and filledwith merchandise, such as candy bars, the switching plate 128 mustbe inone of its two positions; otherwise, both members 114 and 116 wouldremain lowered and no shelf 40 or 48 would be released by reciprocationof bar 96. If handle 130 faces outwardly, as shown in FIGS. 1 and 3-6,and locked in place by one end 148 of leaf 146 being in hole 150, plate128 will depress piece 138, and therefore, the member 114. Spring 124permits depression of member 114 while device 110 is held up by theproximal uppermost prong 94 (FIG. 3); rod 118 maintains member 116 inthe up position. (Member 114 is ommitted from FIGS. 3 and 4 forclearness.)

Therefore, all of the tabs 82 are held out of the path of travel of thelugs 106 of bar 96 except the tab 82 corresponding to the lowermostshelf 40 which is held out of the path of travel of the proximal lug 106by member 116. All remaining tabs 82 are held in such inoperativeposition by the lock means next below, i.e., the edges 92 of the legs 90receiving the tangs 84 of the triggers 80, for example, as shown inFIGS. 3 and 14.

Thus, when bar 96 is initially raised away from stop 98, that lowermostlug 106 thereof corresponding to the lowermost shelf 40 will engage thelowermost face of the proximal tab 82 raising the latter and swingingits trigger 80in a direction which moves finger 88 away from latch 56(FIG. 16). Before bar 96 reaches the upper end of its stroke, tab 82will slip off the lug 106 and trigger 80 will swing freely back bygravity until finger 88 engages portion 74 of latch 56, returning tab 82into the path of descent of lug 106. As bar 96 gravitates and lug 106engages the upper face of tab 82, trigger 80 will be caused to swing onits pivot pin 76 to force finger 88 against latch portion 74. Thisshifts portion 74 from beneath the ear 64 of the element 54 of thelowermost shelf 40 (FIG. 17), permitting the latter to gravitate to avertical position (FIG. 10) dumping its product for movement to aposition accessible to the customer.

Spring latch 56 snaps back to the position in which it is yieldablybiased and when shelf 40 is later raised past its horizontal position,ear 64 deflects latch portion 74 to pass the latter. Then, when theshelf is released, car 64 comes to rest on such portion 74 thereabove,holding the shelf substantially horizontal.

Movement of the lowermost shelf 40 to its article discharge conditionalso swings the leg 90, thereby withdrawing edge 92 from beneath thetang 84 of the trigger next above, i.e., the trigger 80 corresponding tothe second from the bottom shelf 40. Such released trigger 80 is thenhanging freely on its pin 76 and its tab 82 is in readiness foractuation by the second cycle of reciprocation of bar 96.

Thus on successive actuations of the bar 96, all of the shelves 40 arereleased progressively, and as the uppermost shelf 40 discharges itsproduct, its prong 94 will move from the position shown in FIG. 3 to thelowered position shown in FIGS. 4 and 8, dropping the device 108. As rod118 descends, the member 116 will drop from the position shown in FIGS.3, 5 and 6 to the position-shown in FIG. 4. Member 116 thereby releasesthe trigger 80 of the lowermost shelf 48 so that the shelves 48 arethereafter released from bottom to top in successive order. When theuppermost shelf 48 releases its device 110, both triangles 156 will havebeen retracted, lowering actuator 152 to operate sold-out switch 154.

' The serviceman then opens the front door of the vending machinecabinet, raises the lowermost shelves 40 and 48 by turning handle 160,and pulls the unit 20 outwardly to a position rendering the remainingshelves 40 and 48 accessible for flipping upwardly in successive orderfrom bottom to top to their horizontal positions for refilling withproducts.

Before closing the cabinet, the serviceman will set the switching plate128 so that vending commences either from the bottom shelf 40 or thebottom shelf 48, depending on which ofthe columns of shelves 40 or 48had products remaining at the time of servicing. If, for example, hereplenished all of the shelves 40 with fresh products, and only certainof the lower shelves 48 with fresh products, it would be desirable todischarge the remaining old products on the upper shelves 48 beforevending from shelves 40. He accomplishes this result merely by turningplate 128 to dispose the handle 132 outwardly. This lowers the member116, and the member 114 remains in the up position, held by device 110,rod 122 and spring 124. After shelves 48 are all emptied, vendingswitches automatically to the shelves 40 as is obvious from the abovedescriptions.

Coin control mechanisms, power means for raising the bar 96 and otherconventional apparatus commonly employed in automatic vending machinesform no part of the present invention and have, therefore, not beenincluded herein. Suffice to point out that the novel features of theinstant invention and the arrangement of all its components permit theuse of any of a number of different types of necessary or desirableassemblies and parts without need for special, complicated or expensivedevelopments.

We claim:

1. In a vending machine:

a first and a second series of vertically spaced article retainers, eachmounted for movement from an articleholding condition to an articledischarge condition;

releasable mechanism for each retainer respectively normally maintainingthe latter in its article-holding condition;

structure operably associated with and common to said mechanismsforreleasing the same consecutively from one end of said first series tothe opposite end thereof and thence from one end of said second seriesto the opposite end thereof;

said structure including a single, reciprocable actuatorreciprocation ofthe-actuator; and said actuator releasing all of the mechanisms of thefirst seoperable to release one mechanism duringeach cycle of ries ofretainersduring a first number of consecutive cy- 2. The invention ofclaim 1, said structure having switching apparatus for rendering theactuator operable to release said mechanisms consecutively from said oneend of said second series to said opposite end thereof and thence fromsaid one end of said first series to said opposite end thereof.

3. In a vending machine:

a first and a secondseries of vertically spaced article retainers, eachmounted for movement from an artieleholding condition to anarticle-discl urgecondition;

releasable mechanism for each retainer respectively normally maintainingthe latter in its article-holding condition; 7

structure operably associated with and common to said mechanisms forreleasing the same consecutively from one end ofsaid first series to theopposite endthereofand thence from one end of said second series to theopposite endthereof; i

said structure including control means adapted for actuation in onedirection-and gravitation in the opposite direction each time a retaineris to be released; and

each mechanism having releasing means operable upon one gravitationofsaid control means. I

4. In a vending machine: I

a first and-a second series of vertically spaced article retainers, eachmounted for movement from an articleholding condition to an articledischarge condition;

releasable mechanism for each' retainer respectively normallymaintaining the latter in its article-holding condition;

structure operably associated with and common to said mechanisms for"releasing the same consecutively from one-end'of said first series tothe opposite end thereof and thence from one end of said secondseries'to the opposite end thereof; 7 said structure including'areleasable member normally inactivating the mechanism for the retainernext adjacent saidone end ofthe second series; and a device operablycoupled with said member and responsive to movement of the retainer nextadjacent said opposite end of the first series to its article dischargecondition for releasing said member. 5. in a vending machine:

a first and a secondstacit of verticallyspaced article retainers, eachmounted for movement from an articleholding condition to an articledischarge condition; releasable mechanismfor each retainerrespectivelynormally maintaining the latter in its article-holdingcondition; structure operably associated with said mechanisms for eitherreleasing the same consecutively from the bottom to the top ofthe firststack and thence from the bottom to the top of the second stack oralternately, from the bottom to the top of the second stack and thencefrom the bottom to the top of the first stack;

said structure including a releasable member for each stackrespectively;

each member being movable from a released position to a positioninactivating the mechanism for the lowermost retainer ofits respectivestack; 7 t

means responsive to movement ofthe uppermost retainer'of the first stackto its article discharge position for moving said member ofthe secondstack to its released position;

means responsive to movement of the uppermost retainer of the secondstack to its article discharge condition for to their article dischargecondition;

moving said member of thefirst stack to its released position; and iswitching apparatus for alternately holding either of said members inits' released position. In a vending machine: p a first and a secondstack of vertically spaced article retainers, each mounted for movementfrom an articleholding condition to anarticle discharge conditionjreleasable mechanism for each retainer respectively normally maintainingthe latter in its article-holding condit n I structure operablyassociated .with said mechanisms ,for either releasing the sameconsecutively from the bottom to the top of the first stack and thencefrom the bottom to the top of the second-stack or alternately. from thebottom to the top of the second stack and thence from the bottom to thetop ofthe first stuck; said struetureincluding:

.a first releasable member movable from it released position to aposition inactivating the mechanism for the lowermost retainer ofthefirst stuck;

a second releasable member movable from it released position to aposition inactivating'the mechanism for meanscoupling the second devicewith the first member formovingthe latter to its released position whenthe' uppermost retainer of the second stack moves to itsarticle,discharge condition; and I switching apparatus for alternatelyholding either of said members in its released position. 7. lnavendingmaehine: Y a front and-a rear stack of vertically spaced,article-receiving shelves, each mounted for movement from anarticleholdingcondition toan article discharge condition; releasablemechanism between the stacks fore ca'ch shelf respectively normallymaintaining the latter in its articleholding condition; a verticallyreciprocablebar between the stacks and common theretofor releasing onemechanism of one of the stacks each time the bar is raised and lowered;

each mechanism having a releasable latch normally holding its shelf insaid article-holding condition and a latch releasing trigger movable toand from a position engagca-' ble by said bar;

eachshelf except the uppermost shelf of each stack having meansreleasing-the trigger next above for movement to said positionengageable by said bar as the shelves mov'e means responsive to movementof the uppermost shelf of the front stack to itsarticle dischargecondition for releasing the trigger of the lowermost shelf of the rearstack;

means responsive to movement of the uppermost shelf of I the rear stackto its article discharge condition for releasing the trigger of thelowermostshelf of the front stack; and

means for holding either of the triggers of the lowermost shelvesagainst movement to said position engageable by I the bar. t

8. ln a vending machine:

a front and a rear stack of vertically spaced, article-receivingshelves, each mounted for movement from an articleholding condition toan article discharge condition;

releasable mechanism between the stacks for each shelf respectivelynormally maintaining the latter in its articleholding condition;

a vertically reciprocable bar between the stacks and common thereto forreleasing said mechanisms consecutively until all shelves of both stackshave moved to their article discharge conditions;

each mechanism having a trigger for releasing the same, said bar' havinga series of trigger trips reciprocable therewith; and

there being a trip for each trigger respectively, each trigger beingmovable to a position for actuation by its corresponding trip uponmovement of the shelf therebelow to its article discharge condition.

9. In a vending machine:

a front and a rear stack of vertically spaced, article receivingshelves, each mounted for movement from an articleholdingcondition to anarticle discharge condition;

releasable mechanism between the stacks for each shelf respectivelynormally maintaining the latter in its articleholding condition;

a vertically reciprocable bar between the stacks and common thereto forreleasing said mechanisms consecutively until all shelves of both stackshave moved to their article discharge conditions;

releasable holding means precluding operation of the mechanisms of oneof the stacks by the bar until all of the shelves of the other stackhave moved to their article discharge conditions; and

means responsive to movement of all of the shelves of said other stackto their article discharge conditions for releasing said holding means.

10. In a vending machine:

a support;

an article retainer mounted on the support for movement from anarticle-holding condition to an article discharge condition;

releasable mechanism having normally interengaging parts on the supportand on the retainer respectively for maintaining the latter in itsarticle-holding condition;

trigger means movable to and from a mechanism releasing position;

control means adapted for actuation in one direction and for gravitationin the opposite direction; and

said control means having trip means for moving the trigger means tosaid position during gravitation of the control means.

11. The invention of claim 10, said trigger meansvbeing disposed formovement by the trip means away from said mechanism when the controlmeans is actuated, and toward said mechanism during gravitation of thecontrol means.

12. The invention of claim 10, said part on the retainer being rigidthereto for movement therewith; said trigger means being carried by saidpart on the retainer for movement therewith and free movement relativethereto.

13. The invention of claim 10, said part on the support comprising ashiftable latch; said trigger means having a latch engaging finger forshifting the latch to a position out of engagement with said part on theretainer during gravitation of the control means.

14. The invention of claim 10, said trigger means having tab meansengageable by said trip means; said tab means being disposed to beraised by the tripmeans when the control means is actuated and to belowered by the trip means during gravitation ofthe control means.

15. in a vending machine:

an element rigidly secured to said shelf for swinging move- I menttherewith; a releasable spring latch mounted on the support and normallyengaging said element to hold the shelf in its articleholding condition;

a trigger carried by said element for swinging movement therewithandfree swinging movement relative thereto;

a vertically reciprocable control bar having a laterally extending trip;

a tab on said trigger engageable by said trip, said tab being disposedto be moved by the trip to swing the trigger in one direction relativeto said element when the bar is raised and tobe moved by the trip toswing the trigger in the opposite direction relative to said elementduring descent of the bar; and

a latch engaging finger on said trigger, said finger being disposed tomove away from the latch when the trigger swings in said one directionrelative to said element and into engagement with the latch to releasethe latter when the trigger swings in said opposite direction relativeto said element.

16. in a vending machine:

a support;

a stack of vertically spaced article retainers, each mounted on thesupport for movement from an article-holding condition to an articledischarge condition;

releasable mechanism for each retainer respectively having normallyinterengaging parts on the support and on the retainer respectively formaintaining the latter in its article-holding condition;

movable trigger means for each mechanism respectively, and shiftablecontrol means common to said retainers having trip means for eachtrigger means respectively;

each-trigger means having a first position out of the path of travel ofits corresponding trip means, a second position within said path oftravel of its said corresponding trip means,-and a third positionreleasing its corresponding structure;

each retainer, except the uppermost of said retainers, having releasablelock means normally maintaining the trigger means of the retainer nextabove in said first position;

each lock means being released by movement of its corresponding retainerto the article discharge condition;

each trigger means moving freely to said second position upon release ofthe lock means next below; and

each trip means engaging the corresponding trigger means, when thelatter is in said second position, and moving the same to said thirdposition upon actuation of said control means.

17. The invention of claim 16, said control means comprising avertically reciprocable bar:

each trip'means comprising a lateral extension on the bar, each triggermeans having a tab disposed to be moved aside by the correspondingextension, when the bar is raised, to a fourth position of the triggermeans where the tab clears the extension; and

each trigger means returning freely to said second position when its tabis cleared by the corresponding extension for reen'gagement of the tabby its extension when the bar descends.

